Mercedes-Benz, Getec, and The Mobility House: Extending the Service Life of Second-Life Large-Scale Storage Systems

The Mercedes-Benz Group, Getec Energie, and The Mobility House are extending the lifecycle of their stationary large-scale storage systems made from vehicle batteries by another five years. The facilities in Lünen and Elverlingsen, which have existed since 2016 and 2018, respectively, have once again been pre-qualified for the provision of primary control reserve (PCR) – the fastest and most critical grid service in the power system. Over 2,000 second-life battery modules from storage systems developed and supplied by Mercedes-Benz Energy will thus continue to be available with 29 MW of power and 31 MWh of capacity to stabilize the power grid.

Strict Qualification Process

In the course of examining stationary battery storage systems by transmission grid operators, demanding criteria must be met to continue operating in the PCR market. These include, in particular, sufficient storage capacity as well as stable and rapid performance adjustment. Despite their five years of use in stationary storage and partially prior use in electric vehicles, the batteries of the corporate association have once again passed this demanding qualification. The confirmed stable storage capacity attests to the low aging of electric car batteries with "proper" management. This is to be ensured through The Mobility House's marketing and operating algorithms.

Grid Stabilization and Value Creation through Stationary Applications

When a battery reaches the end of its service life in the vehicle, it typically still retains about 70 to 80% of its original capacity. This substantial energy reserve opens up the possibility for an extended second life in a stationary battery storage system. Additionally, first-life battery modules can be "kept fit" in stationary applications as a spare parts inventory before they are installed in vehicles. This is only possible with innovative algorithms and modern software, which The Mobility House has been developing and continually refining specifically for the commercialization of electric vehicle batteries since 2015. Recently, the technology company has also started marketing stationary storage units for third parties in the European primary control and energy markets, including prequalification services, among others.

“Additionally, by operating second-life batteries, we are gathering valuable experience for the development of bidirectional and connected charging applications for our vehicles: On the one hand, we have learned how much the flexibility of batteries is worth in the power grid, and on the other hand, how resilient the batteries prove to be in this deployment,” says Eva Greiner, Chief Technology Officer of the Charging Unit at Mercedes-Benz Mobility AG.